U.S. Department of EnergyOffice of Scientific and Technical Information
Collisional alpha transport in a weakly rippled magnetic field
Abstract
To properly treat the collisional transport of alpha particles due to a weakly rippled tokamak magnetic field the tangential magnetic drift due to its gradient (the ∇B drift) and pitch angle scatter must be retained. Their combination gives rise to a narrow boundary layer in which collisions are able to match the finite trapped response to the ripple to the vanishing passing response of the alphas. Away from this boundary layer collisions are ineffective. There the much stronger ∇B drift of the alphas easily balances the small radial drift of the trapped alphas caused by the ripple. As this balance does not vanish as the trapped-passing boundary is approached, a narrow collisional boundary layer is necessary. The solution of this boundary layer problem allows the alpha transport fluxes to be evaluated in a self-consistent manner to obtain meaningful constraints on the ripple allowable in a tokamak fusion reactor. Furthermore, the analysis indicates that the alpha losses are most sensitive to the ripple near the equatorial plane on the high field side.
- Authors:
-
- OSTI
- Publication Date:
- DOE Contract Number:
- FG02-91ER54109
- Research Org.:
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center
- Sponsoring Org.:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES)
- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY
- OSTI Identifier:
- 1880570
- DOI:
- https://doi.org/10.7910/DVN/NDQUET
Citation Formats
Catto, Peter J. Collisional alpha transport in a weakly rippled magnetic field. United States: N. p., 2019.
Web. doi:10.7910/DVN/NDQUET.
Catto, Peter J. Collisional alpha transport in a weakly rippled magnetic field. United States. doi:https://doi.org/10.7910/DVN/NDQUET
Catto, Peter J. 2019.
"Collisional alpha transport in a weakly rippled magnetic field". United States. doi:https://doi.org/10.7910/DVN/NDQUET. https://www.osti.gov/servlets/purl/1880570. Pub date:Mon Jan 07 04:00:00 UTC 2019
@article{osti_1880570,
title = {Collisional alpha transport in a weakly rippled magnetic field},
author = {Catto, Peter J.},
abstractNote = {To properly treat the collisional transport of alpha particles due to a weakly rippled tokamak magnetic field the tangential magnetic drift due to its gradient (the ∇B drift) and pitch angle scatter must be retained. Their combination gives rise to a narrow boundary layer in which collisions are able to match the finite trapped response to the ripple to the vanishing passing response of the alphas. Away from this boundary layer collisions are ineffective. There the much stronger ∇B drift of the alphas easily balances the small radial drift of the trapped alphas caused by the ripple. As this balance does not vanish as the trapped-passing boundary is approached, a narrow collisional boundary layer is necessary. The solution of this boundary layer problem allows the alpha transport fluxes to be evaluated in a self-consistent manner to obtain meaningful constraints on the ripple allowable in a tokamak fusion reactor. Furthermore, the analysis indicates that the alpha losses are most sensitive to the ripple near the equatorial plane on the high field side.},
doi = {10.7910/DVN/NDQUET},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 07 04:00:00 UTC 2019},
month = {Mon Jan 07 04:00:00 UTC 2019}
}